Classifications

• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
  • H04L12/00—Data switching networks
  • H04L12/28—Data switching networks characterised by path configuration, e.g. LAN [Local Area Networks] or WAN [Wide Area Networks]
  • H04L12/40—Bus networks
  • H04L12/407—Bus networks with decentralised control
  • H04L12/413—Bus networks with decentralised control with random access, e.g. carrier-sense multiple-access with collision detection [CSMA-CD]
• • G—PHYSICS
  • G06—COMPUTING; CALCULATING OR COUNTING
  • G06F—ELECTRIC DIGITAL DATA PROCESSING
  • G06F13/00—Interconnection of, or transfer of information or other signals between, memories, input/output devices or central processing units
  • G06F13/14—Handling requests for interconnection or transfer
  • G06F13/36—Handling requests for interconnection or transfer for access to common bus or bus system
  • G06F13/362—Handling requests for interconnection or transfer for access to common bus or bus system with centralised access control
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
  • H04L12/00—Data switching networks
  • H04L12/28—Data switching networks characterised by path configuration, e.g. LAN [Local Area Networks] or WAN [Wide Area Networks]
  • H04L12/40—Bus networks
  • H04L12/407—Bus networks with decentralised control
  • H04L12/413—Bus networks with decentralised control with random access, e.g. carrier-sense multiple-access with collision detection [CSMA-CD]
  • H04L12/4135—Bus networks with decentralised control with random access, e.g. carrier-sense multiple-access with collision detection [CSMA-CD] using bit-wise arbitration
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
  • H04L12/00—Data switching networks
  • H04L12/28—Data switching networks characterised by path configuration, e.g. LAN [Local Area Networks] or WAN [Wide Area Networks]
  • H04L12/40—Bus networks
  • H04L2012/40208—Bus networks characterized by the use of a particular bus standard
  • H04L2012/40215—Controller Area Network CAN
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
  • H04L12/00—Data switching networks
  • H04L12/28—Data switching networks characterised by path configuration, e.g. LAN [Local Area Networks] or WAN [Wide Area Networks]
  • H04L12/40—Bus networks
  • H04L2012/40267—Bus for use in transportation systems
  • H04L2012/40273—Bus for use in transportation systems the transportation system being a vehicle
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
  • H04L41/00—Arrangements for maintenance, administration or management of data switching networks, e.g. of packet switching networks
  • H04L41/04—Network management architectures or arrangements

Definitions

• the invention relates to media access control methods for controlling access by a subscriber station of a bus system to a first channel of the bus system shared by a plurality of subscriber stations, the method providing to the subscriber station at least one enable interval within which the subscriber station has exclusive access to the first channel.
• the invention also relates to a subscriber station and a control, in particular a CAN controller, which are set up to carry out such a method.
• CAN Controller Area Network
• TTCAN Time Triggered CAN
• the media access control method used in the CAN is based on bitwise arbitration. In the bitwise arbitration several subscriber stations can simultaneously transmit data via the channel of the bus system, without this disrupting the data transfer. The subscriber stations can continue at
• bitwise arbitration is usually done in an arbitration field within a channel to be transmitted over the channel
• the Completely has sent the arbitration field to the channel, it knows that it has exclusive access to the channel.
• the end of the transmission of the arbitration field corresponds to a beginning of a release interval within which the subscriber station can exclusively use the channel.
• other subscriber stations may not access the channel, that is, send data to the channel until the transmitting subscriber station has transmitted a checksum field (CRC field) of the data frame.
• CRC field checksum field
• bitwise arbitration achieves non-destructive transmission of the data frame via the channel. This results in good real-time characteristics of the CAN, whereas in media access control methods in which the data frame sent by a subscriber station is due to a collision with another transmitted by another station
• Data frame during transmission over the channel can be destroyed, have a significantly less favorable real-time behavior, as it comes to a delay of the data transmission due to the collision and thus required new transmission of the data frame.
• TTCAN time division Multiple Access
• a timeslot structure is defined that includes multiple consecutive time slots (often referred to as "time slots") and repeats regularly.
• time slots consecutive time slots
• a particular time slot within which messages of this message type may be transmitted, can be assigned to a specific message type and thus to a specific subscriber station.
• certain time slots are provided within which a particular station has exclusive access to the channel of a CAN domain.
• access to the channel is at least partially coordinated according to the Time Division Multiple Access (TDMA) principle.
• TDMA Time Division Multiple Access
• the protocols of the CAN or its extension TTCAN are particularly suitable for transmitting short messages under real-time conditions.
• larger data blocks are to be transmitted via a CAN domain, then makes the relatively low bit rate of the channel disturbing.
• bit rate can be reduced by reducing the bit rate
• DE 101 53 085 A1 proposes to temporarily transfer the communication interface for transferring the data block to another Switching communication mode, in which no bitwise arbitration is performed and thus a relatively high bit rate is possible.
• the communication with the protocols of the CAN must be interrupted for a certain time. If, for example, the operation of the bus system according to the CAN protocols can no longer be recorded due to an error, then the bus system will fail.
• the transmission of a relatively large data block results in a considerable delay of the subsequent ones to be undertaken according to the protocols of the CAN
• the object of the invention is therefore to specify a method for controlling the access of a subscriber station of a bus system to a shared channel of several subscriber stations, in which large amounts of data can be transmitted relatively quickly and
• Controlling the access to the first channel the bitwise arbitration, by the a bit rate of the first channel is limited, whereas no separate arbitration is required for the second channel.
• a subscriber station has exclusive access to the first channel within the enable interval, and accesses the second channel only if it has exclusive access to the first channel.
• the second channel may have a significantly higher bit rate than the first channel.
• the subscriber station may transmit a relatively large block of data over the second channel while having exclusive access to the first channel.
• the bus system preferably has a CAN domain.
• a time window or a part of the time window within a regularly repeating time window structure is specified as the at least one release interval.
• the release interval or the time window is preferably determined by means of the protocols of the
• the time window may be a section of a base cycle that is repeated several times within a complete cycle. Since in TTCAN a time window is usually assigned to a specific message type, a single subscriber station often has several timeslots and thus several
• TTCAN not only ensures interference-free communication between several subscriber stations via the second channel, without the need for a separate arbitration procedure for the second channel, but also assigns a specific share of the capacity of the second channel to individual subscriber stations. This allows for transfers between two specific subscriber stations or for
• a start of the release interval is determined by the subscriber station by means of bitwise arbitration of the first channel and predetermines an end of the release interval is as soon as the subscriber station after successful arbitration of the first channel releases this again. This ensures that the access to the second channel is controlled by means of the bitwise arbitration provided for the first channel.
• the beginning of the enable interval corresponds to the end of the transmission of an arbitration field of a frame and the end of the enable interval corresponds to an end of the transmission of a checksum field of this frame (CRC field).
• first data to be transmitted via the first channel and second data to be transmitted via the second channel are transmitted via a common signal line. It is therefore sufficient to provide a single signal line, for example in the form of a common bus line between the individual subscriber stations. It is conceivable that this is a bus line of a known bus system, in particular the CAN, is transmitted via the data of the first channel according to the protocols of the CAN. This has the advantage that conventional subscriber stations, which, for example, master the well-known protocols of the CAN, can be connected to the bus system without any problems, which can be combined with the invention
• the proposed method is an extension of the protocols of the CAN, which is compatible with the known protocols and devices of the CAN.
• a data signal and a signal modulated with the second data are formed as a function of the first data, and that the data signal is superposed with the modulated signal.
• a modulation method for forming the modulated signal for example, a frequency modulation, in particular a frequency shift keying function of a logical state (0 or 1) of the second channel can be used.
• a phase modulation for example a binary phase shift keying (BPSK).
• the first data of the first channel can be transmitted via a first signal line and the data of the second channel a second signal line separated from the first signal line.
• the first signal line may be a bus line according to the specification of the CAN, whereas the second signal line may be constructed in any desired manner.
• It may be, for example, another CAN bus line, but operated at a relatively high bit rate. Any number of bit transmission devices can be used. It is also conceivable to use transceiver circuits and signal lines provided for local computer networks, in particular for Ethernet. This allows a high bitrate of the second
• the second signal line can also be formed by an electrical system of the motor vehicle, if in the
• a data transmission device for transmitting data via the electrical system of the motor vehicle is provided (so-called powerline communication, PLC).
• a subscriber station of a bus system with the features of claim 7 is proposed. With such a subscriber station, it is ensured during operation of the bus system that there is no destruction of the data to be transmitted via the second channel as a result of collisions on the second channel. Because each subscriber station connected to the bus system ensures that to everyone
• the subscriber station may be, for example, an electronic component of a motor vehicle, in particular a control device of a motor vehicle.
• the subscriber station has a second control for controlling access to the second channel.
• the second control may be any kind of communication controller that does not need to execute a protocol for controlling access to the second channel.
• the communication controller can easily act as a controller for sending and
• Receiving an asynchronous serial data stream can be realized.
• the second control element is coupled to the first control element such that the second control element, preferably by means of an access control signal generated by the first control element, to enable access to the second channel is controllable.
• the first control element has an output for outputting the access control signal and the second control element has a corresponding control input, which is connected to the
• the subscriber station has a coupling element with which the two control elements can be connected to a common signal line such that the first data and the second data can be transmitted via the common signal line between different subscriber stations.
• the subscriber station has a first transceiver circuit for connecting the subscriber station to a first signal line and a second transceiver circuit for connecting the subscriber station to a second signal line separated from the first signal line.
• a first transceiver circuit for connecting the subscriber station to a first signal line
• a second transceiver circuit for connecting the subscriber station to a second signal line separated from the first signal line.
• the subscriber station is preferably set up to carry out the method according to the invention, so that it realizes its advantages.
• control having the features of claim 13 is proposed.
• the control is preferably a CAN controller.
• control or the CAN controller can be compared to known
• Controls or CAN controllers be extended so that the control or the CAN controller is configured to generate an access control signal indicating whether the second channel is enabled by the control for access by the subscriber station.
• the control or the CAN controller may have an output for outputting the access control signal.
• control element or the CAN controller is set up to carry out the method according to the invention.
• the control or the CAN controller can be realized by means of at least one integrated circuit.
• the integrated circuit may be, for example, an application-specific integrated circuit (ASIC) or a suitably programmed logic circuit (PLD).
• ASIC application-specific integrated circuit
• PLD suitably programmed logic circuit
• Figure 1 is a schematic representation of a bus system with multiple subscriber stations
• Figure 2 is a schematic representation of one of the subscriber stations of Figure 1 according to a first preferred embodiment of the present invention
• Figure 3 is a schematic representation of a portion of a subscriber station according to a second preferred embodiment of the invention.
• FIG. 4 shows a time profile of an occupancy of a channel of the bus system
• FIG. 1 shows an overview of a bus system 11 of a motor vehicle, which comprises a plurality of subscriber stations 13, 13a and a first channel 15 shared by these subscriber stations 13, 13a.
• the subscriber stations 13, 13a and the first channel 15 form a CAN domain 17.
• the present invention can be applied not only to CAN but also to other types of communication networks in which an exclusive, at least for certain periods of time. Collision-free access of a station is guaranteed to a common channel.
• the subscriber stations 13, 13a may be, for example, control devices or display devices of the motor vehicle.
• a part of the subscriber stations 13 is connected to a shared by this part of the subscriber stations 13 second channel 19.
• all subscriber stations 13 are connected to both channels 15, 19 except for the subscriber station 13a.
• Subscriber station 13a is a conventional subscriber station 13a, which indeed masters the protocols of the CAN, but is not set up to carry out a method according to the invention.
• the other subscriber stations 13 are extended according to the invention to additional functions, so that they can additionally communicate via the second channel 19.
• conventional subscriber stations 13a and the extended subscriber stations 13 can thus be connected to one another.
• Several conventional subscriber stations 13a may also be provided in the bus system; However, it is also conceivable in the bus system 1 1 only the extended
• FIG. 2 shows an expanded subscriber station 13 in detail.
• This subscriber station 13 has a microcomputer 21, which may be designed, for example, as a microcontroller.
• a first control of the subscriber station in the form of a CAN controller 23 via a first coupling device 25 is connected.
• the subscriber station 13 has a second control element in the form of a communication controller 27 which is connected to the microcomputer 21 via a second coupling device 29.
• the two coupling devices 25, 29 are set up for the exchange of data to be transmitted via the bus system 1 1 as well as configuration, control and status information between the microcomputer 21 and the two control elements 23, 27.
• the communication controller 27 is coupled to the CAN controller 23 such that the CAN controller can control the communication controller 27 by means of an access control signal a generated by it.
• a control input 28 of the communication controller 27 is connected to a control output 24 of the CAN controller 23.
• the subscriber station 13 has a first transceiver circuit, which is designed as a CAN transceiver 31.
• the CAN transceiver 31 is connected to the CAN controller 23 in such a way that first data to be transmitted between the CAN controller 23 and the CAN transceiver 31 can be exchanged via the CAN domain 17, that is to say the first channel 15 (Arrow 33).
• the CAN transceiver 31 is connected to the CAN controller 23 in such a way that the CAN controller 23 can transmit control signals to the CAN transceiver (arrow 35).
• the CAN transceiver 31 is connected to the first channel 15.
• the subscriber station 13 has a second transceiver circuit 37 which is connected to the communication controller 27 for transmitting first data (arrow 39) to be exchanged via the CAN domain 17 and for transmitting control signals (arrow 41) between the communication controller 27 and the second Transceiver circuit 37 connected.
• the second transceiver circuit 37 is connected to the second channel 19.
• the two transceiver circuits 31, 37 may be connected to the microcomputer 21 so that the microcomputer 21 can control the two transceiver circuits 31, 37 and can read status information from the two transceiver circuits 31, 37 (see arrows 43 and 37) 45).
• connection of the microcomputer 21 to the transceiver circuits 31, 37 is optional, the invention can also be realized without such a connection.
• the communication controller 27 and the second transceiver circuit 37 are high degrees of freedom. It's just required that the communication controller 27 and the second transceiver circuit 37 provide a transmission device for transmitting second data between the extended subscriber stations 13. A protocol for controlling media access control to the second channel (Media Access Control Protocol, MAC protocol) need not be performed over the second channel 19.
• the communication controller 27 is configured to send and receive an asynchronous serial data stream.
• a second transceiver circuit 37 for example, a transceiver circuit, which is actually intended for CAN, are used.
• the second transceiver circuit 37 can be operated at a bit rate which is higher than that for the operation of the second transceiver circuit according to FIGS Protocols of the CAN allowed bitrate. If the two Transeiver circuits 31, 37 are identical design as a CAN-T ransceiver, then the second channel 19 can be operated at a higher bit rate than the first channel 15.
• the bit rate of the second channel 19 may be 3 to 4 Mbit / s, for example.
• the transceiver circuit 37 used can be, for example, a transceiver circuit for the "FlexRay" communication system or for local computer networks, such as "Ethernet", as the second transceiver circuit 37.
• a bit rate of 10 Mbit / s or 100 Mbit / s can be realized on the second channel 19.
• the second channel 19 may act as an electrical and / or an optical connection between the second
• Transceiver circuits 37 of the subscriber stations 13 may be formed.
• the second channel can also be formed by an electrical system 49 of a motor vehicle in which the bus system 1 1 is installed ("powerline communication", PLC).
• PLC powerline communication
• Circuit 37 a PLC modem 47 which is coupled to the electrical system 49 of the motor vehicle for transmitting the second data via the on-board network 49.
• the first channel 15 is formed by a first signal line 51.
• the second channel 19 is replaced by one of the first signal line 51 separate second signal line 53 is formed.
• the first signal line 51 is, for example, a two-wire line which is customary in CAN for the differential transmission of the first data to be transmitted via the first channel 15 (shown in FIG. 2 as the first bit stream bi).
• the second signal line 53 is set up to transmit data to be transmitted via the second channel 19, that is to say to transmit a second bit stream b 2 .
• the second signal line 53 may be configured as a further two-wire line for the differential transmission of the second data b 2 or the second bit stream b 2 or in another way.
• FIG. 3 shows an embodiment in which a common signal line 55 is provided for the two channels 15, 19.
• the common signal line 55 comprises a pair of conductors consisting of a first conductor CANH and a second conductor CANL.
• the common signal line 55 is a conventional bus line suitable for a CAN-based bus system.
• the CAN transceiver 31 is also present in a subscriber station 13 which is designed for connection to the common signal line 55.
• the CAN transceivers 31 are also present in a subscriber station 13 which is designed for connection to the common signal line 55.
• the CAN transceivers 31 are also present in a subscriber station 13 which is designed for connection to the common signal line 55.
• a common mode choke 59 is arranged. Between the common mode choke 59 and the pair of wires CANH, CANL the common signal line 55 is a coupling element 61st. In addition, between the first conductor CANH and the second conductor CANL a bus termination circuit 63 is arranged, which has two series-connected terminating resistors 65, wherein the outer
• this series circuit Ends of this series circuit are connected to the conductors CANH, CANL and a center tap of this series circuit is connected via a capacitor 67 to ground.
• the common mode choke 59 and / or the bus termination circuit 63 is not provided.
• the coupling element 61 belongs to a connection circuit 69 of the subscriber station 13, which is provided in the embodiment shown in Figure 3 instead of the second transceiver circuit 37.
• a modem 71 of the connection circuit 69 is connected on the one hand to the microcomputer 21 and on the other hand connected to the coupling element 61.
• the modem 71 has a modulator 73 for generating one in response to the second Bitstream b 2 modulated signal m.
• the modem 71 has a demodulator 75 for demodulating the modulated signal m transmitted from another subscriber station 13 via the common signal line 55.
• the microcomputers 21 of the individual subscriber stations 13 control the individual CAN controllers 23 and CAN transceivers 31 in such a way that messages can be exchanged between the subscriber stations 13, 13a according to the protocols of the CAN by frames containing the
• the individual subscriber stations 13 support the extension TTCAN.
• TTCAN time is divided into regular, repetitive cycles.
• Overall cycle 77 is shown schematically in FIG.
• the total cycle 77 starts at time t 0 and ends at time t m . It can be seen that the overall cycle 77 is again subdivided into a plurality of basic cycles 79. In the illustrated embodiment, the overall cycle 77 is divided into four basic cycles 79.
• the first base cycle 79 (shown in FIG. 4 above) begins for
• the second basic cycle 79 following the first basic cycle 79, which ends at a time t b2 also begins.
• the third base cycle begins at time t b2 and ends at time t b3 .
• the fourth base cycle begins at time t b3 and ends at time t m , thus ending the overall cycle 77.
• the individual base cycles 79 are divided into a plurality of, in the embodiment shown, six time slots 81, the subdivision of the base cycles 79 into the time slots 81 being identical for each base cycle 79.
• a regularly repeating time window structure is defined, which has a matrix-like structure due to the identical subdivision of the individual base cycles 79 into the time windows 81 and is thus usually referred to as a communication matrix.
• a first time window 81 a is provided for the transmission of reference messages via the first channel 15.
• the reference messages are used in particular for synchronization of the individual subscriber stations 13 with one another, so that the temporal position of the individual time slots 81 from the point of view of the individual subscriber stations 13 is at least substantially the same.
• Time window 81 is assigned to a specific message type, that is to say that within these time windows 81 only data frames with a specific identifier are transmitted. For example, it may be provided that the time slots 81 labeled 81b are reserved for transmitting the message of the particular type.
• Release interval AT 1 , AT 2 , AT 3 and AT 4 within which this subscriber station 13 has exclusive access to the first channel 15.
• the release interval AT 1 , AT 2 , AT 3 and AT 4 ends in each case at the end of the associated time window 81 b, that is to say at the time t e1 , t e2 , t e3 or t te4 . In the embodiment shown this corresponds
• Release interval AT 1 , AT 2 , AT 3 and AT 4 the respective time window 81 b of the overall cycle. Deviating from this, however, it can also be provided that the release interval only AT 1 , AT 2 , AT 3 and AT 4 corresponds to a part of the respective time window 81 b.
• Essential for the function of the method according to the invention is that the release interval AT 1 , AT 2 ,
• AT 3 or AT 4 is temporally completely covered by a time window 81 b or by several immediately consecutive time windows 81 b.
• Each subscriber station 13 acquires the times t 0 , t b1 , t b2 , t b3 at which the individual reference messages are received and calculates the temporal position of at least those time slots 81 within which it wishes to access the bus.
• the CAN Controller 23 prepares these calculations. However, it may also be provided that these calculations are performed by the microcomputer 21. Further, the CAN controller 23 generates the access control signal a and supplies it to the communication controller 27 (see FIG. 2).
• the access control signal a is always active within the release interval AT 1 , AT 2 , AT 3 or AT 4 .
• the communication controller 27 evaluates the access control signal a and accesses the second channel 19 only when the access control signal a is active. If the access control signal a is not active, the communication controller 27 keeps the second channel 19 free, so that other subscriber stations 13 can access the second channel 19.
• the subscriber stations 13 are thus set up such that the CAN controller 23 controls the communication controller 27 in dependence on the access control method carried out in the CAN domain such that the communication controller 27 accesses the second channel 19 only if, according to the media access control method, the CAN controller Domain 17 access to the first channel 15 is allowed.
• time slots 81 c are provided within the overall cycle within which messages of any type may be transmitted. Within these time slots 81c exclusive access of a particular station to the first channel is not guaranteed. Therefore, a bitwise arbitration according to the protocols of the CAN is performed within the time window 81 c. The bitwise arbitration is based on the fact that in case several subscriber stations 13 access the first channel 15 at the same time and send bits with different values, one bit with a certain value is always received by all the stations. The value of this bit is referred to as a "dominant bit" and corresponds to the value 0 in the example shown. Further, the first signal line 51 is constructed such that each subscriber station 13 can receive via its CAN transceiver 31 while accessing the first channel 15. Thus, each subscriber station 13, while accessing the first channel 15 to send a bit, may read the current state of the first channel 15 to determine if that state corresponds to the transmitted bit.
• FIG. 5 shows a section of a time profile of the logic state (value 0 or 1) of the first channel 15 within the time window 81c.
• Idle time 82 in which the first channel 15 from no subscriber station 13th was occupied, an observed subscriber station 13 starts to send a start bit 83 of a frame 85.
• the subscriber station 13 After transmission of the start bit 83, the subscriber station 13 sends an arbitration field 87, which in particular contains the identifier of the message indicating the type of the message. During the transmission of the arbitration field 87, the subscriber station 13 compares the logical one
• a subscriber station 13 exclusive access to the first channel 15 has. All other stations that have simultaneously accessed the first channel 15 to transmit a frame 85 have their transmission and thus their access to the first channel 15 terminated at time t a5 . Thus, the time t a5 corresponds to the beginning of a further release interval AT 5 .
• the subscriber station 13 After sending the arbitration field 87, the subscriber station 13 sends a control field 89 of the frame 85, a data field 91 of the frame 85 and a check field 93 (so-called CRC field).
• an acknowledgment field 95 following the test field 93, other subscriber stations 13 can transmit an acknowledgment bit via the first channel 15, that is, access the first channel 15.
• the release interval AT 5 within which the subscriber station 13 under consideration has exclusive access to the first channel 15 ends at the end of the transmission of the test field 93, that is, at a time t e5 .
• the acknowledgment field 95 is followed by a field with stop bits 97.
• the release interval can also be selected to be shorter; however, it must be within the interval AT 5 in which the subscriber station 13 has exclusive access to the first channel 15.
• the CAN controller 23 ensures that the access control signal a is active only during the release interval AT 5 , so that the communication controller 27 accesses the second channel 19 within the time slots 81 c only during the release interval AT 5 . Notwithstanding the embodiment shown, it can also be provided that the CAN controller 23 releases the release signal a for enabling access to the second channel 19 only within such time slots 81, which releases for transmitting messages of a certain type, that is, for example, within the time slots 81 b. While those timeslots (eg the
• Time window 81 c which are used for transmitting messages of different types, that is, within which the bitwise arbitration takes place, the second channel 19 is not used in this embodiment. It is also conceivable that an access to the second channel during the interval AT 5 is only released if TTCAN, for example due to an error in the
• the invention is applied to a CAN domain 17, which does not support the extension TTCAN.
• a CAN domain 17 In such a CAN domain 17, the time window structure 77 is missing. Thus, a bitwise arbitration always takes place there.
• access to the second channel 19 is enabled during the release interval AT 5 drawn in FIG.
• the second transceiver circuit 37 If the access control signal a is active, that is to say the access to the second channel 19 is enabled, then in the case of the embodiment shown in FIG. 2, the second transceiver circuit 37 outputs the second bitstream b 2 . If the second signal line 53 is formed by the on-board network 49, the PLC modem 47 modulates the bit stream b 2 at the transmitting subscriber station 13 and outputs a correspondingly modulated signal to the on-board network 49. At the receiving subscriber stations 13, the PLC modem 47 demodulates the modulated signal output from the transmitting subscriber station 13 and thereby reconstructs the transmitted bitstream b 2 and outputs that in the second
• Bitstream b 2 second data to the communication controller 27 on.
• the modulator 73 of the modem 71 generates the transmitting subscriber station 13 in response to the second data b 2 sent to the communication controller 27 Connection circuit 69 has transmitted, the modulated signal m.
• the coupling element 61 superimposes a data signal d generated by the CAN transceiver 31 as a function of the first bit stream bi with the signal m modulated in dependence on the second bit stream b 2 and outputs it to the two conductors CANH and CANL of the common signal line 55.
• the coupling element 61 Subscriber stations 13, the coupling element 61, a signal received via the two conductors CANH and CANL signal to the CAN transceiver 31 on, optionally via the common mode choke 59, and supplies it to the demodulator 75 of the modem 71.
• the CAN transceiver 31 extracts the first bit stream bi from the received signal and forwards it to the CAN controller 23.
• the demodulator 75 determines the second bit stream b 2 from the received signal.
• the modem 71 uses a frequency shift keying as a modulation method as a function of the value of the individual time-sequential bits of the second bit stream b 2 . Deviating from this, a phase modulation or any other modulation method can be used instead of the frequency shift keying.
• the coupling element 61 may be formed in the simplest case as a resistor network. However, it can also be provided that the coupling element 61 has one or more filters for separating the data signal d to be fed from the CAN transceiver 31 from the modulated signal m. Furthermore, it would be conceivable that the coupling element 61 with the
• Common mode choke 59 is combined, for the common mode choke 59 so instead of a simple inductance with four terminals, an inductor with six or more terminals is used. In this way, the RF signal can be inductively switched on and / or out and the RF part is galvanically decoupled from the CAN bus. In addition, this results in cost advantages.
• the present invention provides a method and a subscriber station 13, which makes it possible to significantly increase the useful bit rate of the CAN domain 17 by means of the additional, second channel 19, so that larger data blocks can be transmitted without problems via the bus system 11. Since the access to the second channel 19 in dependence on the

Landscapes

• Engineering & Computer Science (AREA)
• Computer Networks & Wireless Communication (AREA)
• Signal Processing (AREA)
• Theoretical Computer Science (AREA)
• Physics & Mathematics (AREA)
• General Engineering & Computer Science (AREA)
• General Physics & Mathematics (AREA)
• Small-Scale Networks (AREA)
• Bus Control (AREA)
• Information Transfer Systems (AREA)

Priority Applications (8)

Applications Claiming Priority (2)

Publications (1)

Family

ID=42288949

Family Applications (1)

Country Status (10)

Families Citing this family (12)

Citations (3)

Family Cites Families (11)

• 2009
  • 2009-06-16 DE DE102009026965A patent/DE102009026965A1/de not_active Withdrawn
• 2010
  • 2010-06-09 US US13/377,886 patent/US8824493B2/en active Active
  • 2010-06-09 CN CN201080026678.7A patent/CN102804697B/zh active Active
  • 2010-06-09 WO PCT/EP2010/058098 patent/WO2010145980A1/de active Application Filing
  • 2010-06-09 KR KR1020127001005A patent/KR101719385B1/ko active IP Right Grant
  • 2010-06-09 BR BRPI1014496-0A patent/BRPI1014496B1/pt not_active IP Right Cessation
  • 2010-06-09 EP EP10721829A patent/EP2443797B1/de active Active
  • 2010-06-09 ES ES10721829T patent/ES2406779T3/es active Active
  • 2010-06-09 JP JP2012515433A patent/JP5390701B2/ja not_active Expired - Fee Related
  • 2010-06-09 RU RU2012100870/08A patent/RU2562363C2/ru active

Patent Citations (3)

Also Published As

Similar Documents

Legal Events